不同水盐条件下马蔺叶片的渗透调节效应

Osmotic Adjustment of Ⅰ.lactea var.chinensis Leaves Under Interactions of Soil Moisture and Salinity

【目的】研究多年生草本鸢尾科植物-马蔺(Iris lactea Pall.var.chinensis(Fisch.)Koidz.)在盐分和水分共同作用下的生长变化及渗透调节效应,为马蔺的栽培利用提供科学依据。【方法】以砂培马蔺幼苗为试材,分别设置5个NaCl浓度(S)(0、0.5%、1.0%、1.5%和2.0%)和3种土壤含水量(W)(田间持水量的100%、65%和45%)交互组合为15个处理。幼苗处理8 d后测定地上部无机离子、脯氨酸(Pro)和可溶性糖(SS)含量,并计算其对渗透势的贡献度。【结果】马蔺在土壤水分充足且盐分较低时生长良好,盐浓度在1.5%—2.0%时,地上部生物量明显减小,但在2.0%NaCl处理中,65%土壤含水量下马蔺地上部生物量相比于充足供水提高了14%。土壤含水量为45%时,盐浓度由0.5%增至1.0%后,植株生物量并无减小。在各盐胁迫浓度下,随着土壤含水量的降低,植株生长减缓且体内Na+、Cl-以及脯氨酸含量都大幅增高。水分的减少明显提高了无机离子的渗透调节作用,在1.5%NaCl和45%土壤含水量(W45S1.5)下,无机离子对总渗透势的贡献度高达90%,土壤含水量对脯氨酸和可溶性糖的渗透势贡献度无显著影响。【结论】在高浓度NaCl下,适量的水分供应可以改善植株的生长,且干旱条件下盐分在一定程度上有提高植株抗性的作用。相比于盐浓度的提高,水分的减少更能提高无机离子对渗透调节作用的贡献度,马蔺的无机物的渗透调节效应远大于有机物的渗透调节。

【Objective】The objective of this study was to investigate the growth changes and osmotic adjustment of perennial herbaceous Iris plant（Iris lactea Pall.var.chinensis（Fisch.）Koidz.）under interactions of soil moisture and salinity,and to provide a scientific basis for cultivation and utilization of I.lactea var.chinensis【.Method】I.lactea var.chinensis seedlings under sand culture condition were treated with the 15 cross combinations of different NaCl concentrations of 0（CK）,0.5,1,1.5,and 2% and three soil moisture levels of 100,65,and 45%（of field capacity）.After 8 d treatment,the contents of inorganic ions,proline（Pro） and soluble sugar（SS） in shoots were determined,respectively,and their contributions to the osmotic potential were calculated.【Result】The optimal growth condition for I.lactea var.chinensis was high soil moisture and low salinity,1.5%-2% NaCl caused a significant decrease in shoot biomass,while decrease in soil moisture from 100% of field capacity to 65% resulted in a 14% increase in shoot biomass at 2% NaCl.At 45% of field capacity,biomass was not significantly different between 0.5% and 1% NaCl.Contents of Na＋,Cl-and Pro in shoots significantly increased with the decrease of moisture levels of soil.More inorganic ions played an important role in osmotic adjustment with soil moisture decreasing,estimated contribution of inorganic ions to osmotic potential was 90% at 1.5% NaCl combined with 45% of field capacity.It had no significant effect on estimated contribution of Pro and SS to osmotic potential.【Conclusion】The growth of I.lactea var.chinensis at high salinity was increased by moderate moisture level,and the drought tolerance of I.lactea var.chinensis was improved by moderate salinity.As soil moisture decreased,inorganic ions played a more important role in osmotic adjustment,more inorganic ions but less organic osmoticum were involved in osmotic adjustment in leaves of I.lactea var.chinensis.